Anti-ferroelectric liquid crystal composition

Abstract

Provided are an anti-ferroelectric liquid crystal composition consisting essentially of (a) a swallow-tailed compound of the formula (1), (b) an anti-ferroelectric liquid crystal compound of the formula (2), and (c) a phenyl ester compound of the formula (3), and a liquid crystal display device using the composition, The above anti-ferroelectric liquid crystal composition has an anti-ferroelectric phase in a broad temperature range, has a high response time I in the transition from an anti-ferroelectric state to a ferroelectric state and a proper response time II in the transition from a ferroelectric state to an anti-ferroelectric state, and can therefore provide an anti-ferroelectric liquid crystal display device having high display quality.

What is claimed is: 
     
       1. An anti-ferroelectric liquid crystal composition consisting essentially of: (a) a swallow-tailed compound of the formula (1),   (b) an anti-ferroelectric liquid crystal compound of the formula (2), and   (c) a phenyl ester compound of the formula (3), ##STR3##  wherein, in the formula (1), R 1  is a linear alkyl group having 4 to 10 carbon atoms, X is a hydrogen atom or a fluorine atom, and m is an integer of 2 or 3;   in the formula (2), R 2  is a linear alkyl group having 6 to 12 carbon atoms, Y is a hydrogen atom or a fluorine atom, A is --CH 3  or --CF 3 , r is 0 or 1, provided that r is 0 and p is an integer of 4 to 10 when A is --CH 3  and that p is an integer of 6 to 8 when A is --CF 3  and r is 0 and that s is an integer of 5 to 8 and p is an integer of 2 or 4 when A is --CF 3  and r is 1, and C* is an asymmetric carbon atom; and   in the formula (3), R 3  is a linear alkyl group having 5 to 10 carbon atoms, Z is a hydrogen atom or a fluorine atom, and n is an integer of 5 to 10.   
     
     
       2. The composition of claim 1, wherein, in the formula (1), R 1  is a linear alkyl group having 9 carbon atoms, m is 2 and X is a fluorine atom. 
     
     
       3. The composition of claim 1 or 2, wherein, in the formula (2), Y is a fluorine atom, A is --CF 3 , r is 1, s is an integer of 5 to 8, and p is an integer of 2 or 4. 
     
     
       4. The composition of claim 1 or 2, wherein, in the formula (2), Y is a fluorine atom, A is --CH 3 , r is 0, and p is an integer of 4 to 6. 
     
     
       5. The composition of claim 1 or 2, wherein, in the formula (3), R 3  is a linear alkyl group having 9 to 15 carbon atoms, Z is a fluorine atom, and n is 8. 
     
     
       6. The composition of claim 1, wherein the composition contains 1 to 60 mol % of the swallow-tailed compound of the formula (1), 30 to 80 mol % of the anti-ferroelectric liquid crystal compound of the formula (2) and 1 to 30 mol % of the phenyl ester compound of the formula (3). 
     
     
       7. The composition of claim 1, wherein the composition has at least a smectic A phase in a temperature range of from 0 to 40° C. and has a smectic A phase at a temperature higher than that of the anti-ferroelectric phase. 
     
     
       8. A simple matrix liquid crystal display device comprising the anti-ferroelectric liquid crystal composition of claim 1, which is interposed between a pair of electrode substrates formed by arranging scanning electrodes and signal electrodes in a matrix form. 
     
     
       9. The composition of claim 3, wherein, in the formula (3), R 3  is a linear alkyl group having 9 to 15 carbon atoms, Z is a fluorine atom, and n is 8. 
     
     
       10. The composition of claim 4, wherein, in the formula (3), R 3  is a linear alkyl group having 9 to 15 carbon atoms, Z is a fluorine atom, and n is 8.